Implement NOWAIT option for BASE_BACKUP command

Specifying this option makes the server not wait for the
xlog to be archived, or emit a warning that it can't,
instead leaving the responsibility with the client.

This is useful when the log is being streamed using
the streaming protocol in parallel with the backup,
without having log archiving enabled.

1 files changed, 14 insertions, 1 deletions

diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index b93c268167d..c09d961d67e 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -1473,7 +1473,7 @@ The commands accepted in walsender mode are:
   </varlistentry>
 
   <varlistentry>
-    <term>BASE_BACKUP [<literal>LABEL</literal> <replaceable>'label'</replaceable>] [<literal>PROGRESS</literal>] [<literal>FAST</literal>] [<literal>WAL</literal>]</term>
+    <term>BASE_BACKUP [<literal>LABEL</literal> <replaceable>'label'</replaceable>] [<literal>PROGRESS</literal>] [<literal>FAST</literal>] [<literal>WAL</literal>] [<literal>NOWAIT</literal>]</term>
     <listitem>
      <para>
       Instructs the server to start streaming a base backup.
@@ -1530,6 +1530,19 @@ The commands accepted in walsender mode are:
          </para>
         </listitem>
        </varlistentry>
+
+       <varlistentry>
+        <term><literal>NOWAIT</literal></term>
+        <listitem>
+         <para>
+          By default, the backup will wait until the last required xlog
+          segment has been archived, or emit a warning if log archiving is
+          not enabled. Specifying <literal>NOWAIT</literal> disables both
+          the waiting and the warning, leaving the client responsible for
+          ensuring the required log is available.
+         </para>
+         </listitem>
+       </varlistentry>
       </variablelist>
      </para>
      <para>